The present invention relates to an ink jet printhead comprising a channel plate having a plurality of ink channels etched into at least one surface thereof, actuators respectively associated with each of the ink channels for pressurizing ink contained in the ink channels, and means defining an ink reservoir communicating with the ink channels. The present invention also relates to a method for manufacturing such a printhead.
An example of a conventional printhead of this type is described in EP-A-0 671 372. The ink channels are arranged side-by-side in one surface of the channel plate and extend in parallel to one another with narrow spacings formed therebetween. Each ink channel converges into a nozzle at one end thereof, so that an array of nozzles is formed, by which a plurality of ink droplets can be expelled simultaneously by energizing the actuators respectively associated with the ink channels. For a high-resolution printer, it is required that the spacings between the adjacent nozzles are made as small as possible, and, accordingly, the ink channels and the wall portions separating them must have very small dimensions in the width direction.
The ink reservoir defining means and the channel plate are formed by a one-piece substrate made of a material such as silicon, in which the ink channels can be formed by photo-lithographic etching. This has the advantage that the minute structures of the ink channels and the nozzles can be formed with high accuracy. Cavities defining the ink reservoir and supply passages connecting the ink reservoir to each of the ink channels are formed directly in the silicon substrate by etching away appropriate portions of the substrate.
As an alternative, it has been proposed to form the channel plate and the ink reservoir defining means by a one-piece block of graphite. In this case, however, the ink channels must be cut into the surface of the channel plate, and the process of forming the minute structures of the ink channels and nozzles becomes more cumbersome or a graphite with a very small grain size must be used which makes the inkjet printhead expensive.